PROCESS FOR PREPARATION OF 4,6-DIAMINORESORCINOL OR SALTS THEREFORE

摘要

A process for producing 4,6-diaminoresorcinol or its salt which comprises reducing by hydrogenation in the presence of a metallic catalyst 4,6bis(substituted)phenylazoresorcinol represented by general formula (1) (for example, 4,6-bisphenylazoresorcinol) to give 4,6-diaminoresorcinol or its salts. In said formula, represent each halogeno, C1-5 alkyl, hydroxycarbonyl or C1-5 alkoxy, provided that two or more Rs may be either the same or different from each other; and n is 0 or an integer of from 1 to 5; characterized by using an aliphatic nitrile compound (for example, acetonitrile) as a solvent, or effecting the reduction by using at least one organic solvent selected from among aliphatic nitrile compounds, aliphatic C35 alcohols, dioxane, ethylene glycol monomethyl ether, etc. in the presence of a filter aid (for example, active carbon). This process makes it possible to easily produce highly pure 4,6-diaminoresorcinol from 4,6-bis(substituted)-phenylazoresorcinol at a high yield.